You'll be fine. This summer I did 1,100 miles fully loaded on my '85 Raleigh Portage from NE Oklahoma to Devil's Tower, Wyoming. I had no mechanical problems. I think the only limitation of 1980s touring bikes is that they predate today's off-road touring (bikepacking) trend and thus can't accommodate the wider tires that make such touring easier. The frames are up to it, but the experience is a bit less seamless on 38 or 42 mm tires than on 2.5" tires.